British Gas owner Centrica has fuelled further controversy over energy prices after reporting another profit rise at its British supply business.
It said operating profits at the energy and services arm covering the UK and Ireland rose by 2% to £906 million last year from £891 million a year earlier, helping wider group operating profits at Centrica jump 4% to £1.5 billion.
The company is expected to face fresh calls to address tariffs for businesses and domestic consumers.
The industry has faced mounting pressure to treat loyal customers fairly and has been criticised for being slow to pass on falls in wholesale gas prices, with consumer groups hitting out at the size and timing of cuts.
British Gas announced it was extending a price freeze on its standard energy tariff until August, "despite increases in external costs", but customers are expecting prices to soar later this year, following the Brexit-induced collapse of the pound and rising wholesale energy prices.
Centrica's British Gas residential energy supply arm, which only covers UK homes, reported an 11% drop in operating profit to £553 million, compared with £623 million in 2015, but said the reduction was due in part to a customer exodus.
More than 409,000 UK home customers left the business in the year to December 31, marking a 3% fall to 14.25 million.
But the group said it stemmed the outflow in the second half of the year after launching new tariffs and improving customer service.
Group chief executive Iain Conn said: "2016 was a year of robust performance and progress in implementing our customer-focused strategy.
"We delivered our key objectives including improved customer service and more innovative offerings and solutions - while repositioning the portfolio, building capability and driving significant cost efficiencies."
British Gas is one of few so-called Big Six energy suppliers to have frozen prices in recent months.
Companies including Npower, EDF and ScottishPower have hiked customer prices, with many blaming rising wholesale costs.
ScottishPower recently announced that standard gas and electricity bills would rise 7.8% from March 31, while Npower set out plans to hike gas and electricity prices by 9.8% - a move that will add £109 to annual dual fuel bills.
Centrica said revenues for 2016 dropped 3% to £27.1 billion, versus £28 billion a year earlier.
But the company managed to swing to a pre-tax profit of £2.2 billion, after reporting a £1.1 billion loss due to a writedown last year.